1. Field of the Invention
Various embodiments of the present invention relate to a fuel cell power management system, and an anti-islanding method using the system.
2. Description of the Related Art
Fuel cells are environmentally friendly energy sources that generate electric energy from, for example, hydrogen, and are highlighted, together with solar cells, as an alternative energy technology. Power generation systems using fuel cells can be classified as stand-alone systems, in which one fuel cell supplies electric power to load, and distributed generation systems that employ a plurality of fuel cells or solar cells to supply electric power to a power grid. A distributed generation system can collect small amounts of electric power output from each fuel cell, and can output large amounts electric power. In addition, even if some of the fuel cells break, other fuel cells can be used to compensate for the lost electric power, and thus, the electric power can be stably supplied. Due to the above advantages, distributed generation systems are being widely developed for domestic and/or industrial use.
FIG. 1 is a diagram illustrating an islanding phenomenon in a distributed generation system. Referring to FIG. 1, electric power is generated by a fuel cell system 12 and is supplied to a load 14, through a power grid 13. The islanding phenomenon refers to when the fuel cell system 12 continues to provide power to the load 14, when no electric power is supplied from the power grid 13. Such islanding phenomenon can damage a normal electric power transmission system, and/or may be harmful to an operator managing the fuel cell system 12 and damage user equipment. Therefore, an anti-islanding technology that disconnects the fuel cell system 12 from the power grid 13, when the electric power from other sources is not supplied to the power grid 13, is required.